Diagnostic impact of echo planar diffusion-weighted magnetic resonance imaging (DWI) in musculoskeletal neoplastic masses using apparent diffusion coefficient (ADC) mapping as a quantitative assessment tool.

Abstract: Purpose: To evaluate the diagnostic impact of echo planar DW imaging in distinguishing benign from malignant musculoskeletal soft-tissue masses using ADC mapping as a quantitative assessment tool. Patients and methods: We evaluated 73 tumors (21 bone tumors and 52 soft-tissue tumors). MR examinations were performed with a 1.5-T system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1000s/mm². ADC value measurements were compared with the histopathological findings. Results: The average ADC of benign tumors was 1.86±0.67×10⁻³ mm²/s, and that of malignant soft-tissue tumors was 0.97±0.35×10⁻³ mm²/s. ADC value of malignant tumors was significantly lower than that of the benign tumor group (p <0.0001). The highest ADC value was seen in the case of ganglion cyst (2.8±0.23×10⁻³ mm²/s) and cystic neurofibroma (2.5±0.04×10⁻³ mm²/s), and juxta cortical enchondroma (2.65±0.36×10⁻³ mm²/s) while the lowest one was seen in aggressive fibromatosis (0.37±0.05×10⁻³ mm²/s). For malignant soft-tissue masses, the highest ADC value was seen in mesenchymal chondrosarcoma (2.1±0.32) liposarcoma (intermediate grade) (1.4±0.21) while the lowest ADC value was seen in fibrosarcoma (high grade) (0.78±0.14). Conclusion: MR diffusion provides additional information to the routine MRI sequences rendering it an effective non-invasive tool in differentiating between benign and malignant soft-tissue tumors. [Copyright &y& Elsevier]